Multi-speed transmission with external drive gearsets

ABSTRACT

A transmission is provided having an input member, an output member, three planetary gear sets, two external gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. Each of the external gear sets includes first and second gears. The torque transmitting devices include clutches and brakes.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of gear sets and a plurality of torque transmitting devices,and more particularly to a transmission having ten or more speedsproduced by a combination of planetary gear sets, external gear sets andtorque transmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches or brakes, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations that exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,three planetary gear sets, two external gear sets, a plurality ofcoupling members and a plurality of torque transmitting devices. Each ofthe planetary gear sets includes first, second and third members. Eachof the external gear sets include first and second gear members. Thetorque transmitting devices are for example clutches and brakes.

An embodiment of the transmission includes an input member, an outputmember, a first, second and third planetary gear set each having afirst, second and third member, a first, second and third gear set eachhaving a first gear intermeshed with a second gear.

In another embodiment of the transmission, a first interconnectingmember continuously interconnects the second gear of the first co-planargear set with the third member of the first planetary gear set.

In still another embodiment of the transmission, a first, second andthird planetary gear sets each having a sun gear, carrier member andring gear. The input member is continuously interconnected with the sungear of the first planetary gear set. The output member is continuouslyinterconnected with the ring gear of the third planetary gear set.

In still another embodiment of the transmission, a first and secondtorque transfer assembly each having a first gear and a second gear.

In still another embodiment of the transmission, a first interconnectingmember continuously interconnecting the first gear of the firstco-planar gear set with the carrier member of the first planetary gearset.

In still another embodiment of the transmission, a secondinterconnecting member continuously interconnecting the ring gear of thefirst planetary gear set with the carrier member of the second planetarygear set.

In still another embodiment of the transmission, a third interconnectingmember continuously interconnecting the ring gear member of the secondplanetary gear set with the sun gear of the third planetary gear set.

In yet another embodiment of the transmission, fourth interconnectingmember continuously interconnecting the carrier member of the thirdplanetary gear set with the first gear of the second co-planar gear set.

In yet another embodiment of the transmission, a first torquetransmitting mechanism selectively engageable to interconnect thecarrier member of the first planetary gear set with at least one of thering gear of the second planetary gear set and sun gear of the thirdplanetary gear set.

In yet another embodiment of the transmission, a second torquetransmitting mechanism selectively engageable to interconnect the secondgear of the first co-planar gear set with the second gear of the secondco-planar gear set.

In yet another embodiment of the transmission, a third torquetransmitting mechanism selectively engageable to interconnect the sungear of the first planetary gear set and the input member with at leastone of the first gear of the second co-planar gear set and the secondcarrier of the third planetary gear set.

In yet another embodiment of the transmission, a fourth torquetransmitting mechanism selectively engageable to interconnect at leastone of the first gear of the second co-planar gear set and the carriermember of the third planetary gear set with the sun gear member of thesecond planetary gear set.

In yet another embodiment of the transmission, a fifth torquetransmitting mechanism selectively engageable to interconnect the ringgear of the first planetary gear set and the carrier member of thesecond planetary gear set with the stationary member.

In yet another embodiment of the transmission, a sixth torquetransmitting mechanism selectively engageable to interconnect the sungear member of the second planetary gear set with the stationary member.

The torque transmitting mechanisms are each selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.

Further aspects and advantages of the present invention will becomeapparent by reference to the following description and appended drawingswherein like reference numbers refer to the same component, element orfeature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a gear set.Solid line levers represent a planetary gear set wherein the three basicmechanical components of the planetary gear set are each represented bya node. Therefore, a single planetary gear set lever contains threenodes: one for the sun gear, one for the planet gear carrier, and onefor the ring gear. Dashed line levers are spur or external drive gearsets which may be represented in the lever diagram as planetary gearsets having grounded planet carrier members. Accordingly, the outernodes represent the first and second drive gears and the inner noderepresents the imaginary grounded planet carrier member. The relativelength between the nodes of each lever can be used to represent thering-to-sun ratio and first drive gear to second drive gear ratio ofeach respective gear set. These lever ratios, in turn, are used to varythe gear ratios of the transmission in order to achieve appropriateratios and ratio progression. Mechanical couplings or interconnectionsbetween the nodes of the various planetary gear sets are illustrated bythin, horizontal lines and torque transmitting devices such as clutchesand brakes are presented as interleaved fingers. Where the torquetransmitting device is a brake, one set of interleaved fingers iscoupled to a ground. Further explanation of the format, purpose and useof lever diagrams can be found in SAE Paper 810102, “The Lever Analogy:A New Tool in Transmission Analysis” by Benford and Leising which ishereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a first external gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C, a second external gear set 22 having three nodes: a first node 22A,a second node 22B and a third node 22C and an output shaft or member 24.

The input member 12 is coupled to the first node 14A of the firstplanetary gear set 14. The output member 24 is coupled to the third node18C of the third planetary gear set 18. The second node 14B of the firstplanetary gear set 14 is coupled to the first node 20A of the firstexternal gear set 20. The third node 14C of the first planetary gear set14 is coupled to the second node 16B of the second planetary gear set16. The first node 16A of the second planetary gear set 16 is coupled tothe first node 18A of the third planetary gear set 18. The second node18B of the third planetary gear set 18 is coupled to the first node 22Aof the second external gear set 22.

A first clutch 26 selectively connects the second node 14B of the firstplanetary gear set 14 and first node 20A of the first external gear set20 to the first node 16A of the second planetary gear set 16. A secondclutch 28 selectively connects third node 20C of the first external gearset 20 to the third node 22C of the second external gear set 22. A thirdclutch 30 selectively connects the input member 12 the first node 14A ofthe first planetary gear set 14 to the second node 18B of the thirdplanetary gear set 18 and to first node 22A of the second external gearset 22. A fourth clutch 32 selectively connects the third node 16C ofthe second planetary gear set 16 to the first node 22A of the secondexternal gear set 22 and to the second node 18B of the third planetarygear set 18. A first brake 34 selectively connects the second node 16Bof the second planetary gear set 16 and the third node 14C of the firstplanetary gear set 14 to a stationary element or transmission housing50. A second brake 36 selectively connects the third node 16C of thesecond planetary gear set 16 to a stationary element or transmissionhousing 50.

Referring now to FIG. 2, a schematic diagram illustrates an embodimentof the ten speed transmission 10 according to the present invention. InFIG. 2, the numbering from the lever diagram of FIG. 1 is carried over.The clutches, brake and couplings or interconnections arecorrespondingly presented whereas the nodes of the planetary gear setsnow appear as components of planetary gear sets such as sun gears, ringgears, planet gears and planet gear carriers and the nodes of theexternal drive gear sets now appear as components of the external drivegear sets such as first and second drive or transfer gears.

For example, planetary gear set 14 includes a sun gear member 14A, aplanet gear carrier member 14B and a ring gear member 14C. The planetgear carrier member 14B rotatably supports a set of planet gears 14Dconfigured to intermesh with both the sun gear member 14A and the ringgear member 14C. The sun gear member 14C is connected for commonrotation with a first shaft or interconnecting member 52 and with inputshaft or member 12. The planet carrier member 14B is connected forcommon rotation with a second shaft or interconnecting member 54 andwith a third shaft or interconnecting member 56. The ring gear member14C is connected for common rotation with a fourth shaft orinterconnecting member 58.

The planetary gear set 16 includes a sun gear member 16C, a planet gearcarrier member 16B and a ring gear member 16A. The planet gear carriermember 16B rotatably supports a set of planet gears 16D configured tointermesh with both the sun gear member 16C and the ring gear member16A. The sun gear member 16C is connected for common rotation with afifth shaft or interconnecting member 60. The planet carrier member 16Bis connected for common rotation with fourth shaft or interconnectingmember 58. The ring gear member 16A is connected for common rotationwith a sixth shaft or interconnecting member 62.

The planetary gear set 18 includes a sun gear member 18A, a planet gearcarrier member 18B and a ring gear member 18C. The planet gear carriermember 18B rotatably supports a set of planet gears 18D configured tointermesh with both the sun gear member 18A and the ring gear member18C. The sun gear member 18A is connected for common rotation with thesixth shaft or interconnecting member 62. The planet carrier member 18Bis connected for common rotation with a seventh shaft or interconnectingmember 64 and an eighth shaft or interconnecting member 66. The ringgear member 18C is connected for common rotation with the output shaftor member 24.

The first external gear set 20 includes a first gear member 20Aintermeshed with a second gear member 20C. The first gear member 20A isconnected for common rotation with the third shaft or interconnectingmember 56. The second gear member 20C is connected for common rotationwith a ninth shaft or interconnecting member 68.

The second external gear set 22 includes a first gear member 22Aintermeshed with a second gear member 22C. The first gear member 22A isconnected for common rotation with the seventh shaft or interconnectingmember 64. The second gear member 22C is connected for common rotationwith a tenth shaft or interconnecting member 70.

In an alternative embodiment of the present invention, coplanar gearsets 20 and 22 are each replaced by sprockets rotationally coupled by achain or belt (represented by the dashed boxes labeled 80 in FIG. 2).More specifically, in the instant embodiment each of the first gearmembers 20A and 22A are replaced by first sprockets and each of thesecond gear members 20C and 22C are replaced by second sprockets.Moreover, a torque transfer chain is provided for each gear or sprocketset 20 and 22. Each of the torque transfer chains mesh with each of thefirst and second sprockets of each of the gear sets to transfer torquebetween the sprockets.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 24 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting elements or the clutches 26, 28, 30, 32 andfirst and second brakes 34 and 36 allow for selective interconnection ofthe shafts or interconnecting members, members of the planetary gearsets and external gear sets, and the transmission housing. For example,the first clutch 26 is selectively engageable to connect the secondshaft or interconnecting member 54 with the sixth shaft orinterconnecting member 62. The second clutch 28 is selectivelyengageable to connect the ninth shaft or interconnecting member 68 withthe tenth shaft or interconnecting member 70. The third clutch 30 isselectively engageable to connect the first shaft or interconnectingmember 52 with the eighth shaft or interconnecting member 66. The fourthclutch 32 is selectively engageable to connect the fifth shaft orinterconnecting member 60 with the seventh shaft or interconnectingmember 64. The first brake 34 is selectively engageable to connect thefourth interconnecting member 58 to a stationary element or thetransmission housing 50 in order to restrict member 58 from rotatingrelative to the transmission housing 50. The second brake 36 isselectively engageable to connect the fifth shaft or interconnectingmember 60 to a stationary element or the transmission housing 50 inorder to restrict member 60 from rotating relative to the transmissionhousing 50.

In the particular example provided, the transmission 10 is arrangedalong two parallel and spaced apart axes including a first axis definedby the input member 12 and a second axis defined by the ninth shaft orinterconnecting member 68. The ninth shaft or interconnecting member 68is an idler shaft. Accordingly, in the example provided, the planetarygear set 14, 16 and 18, the first gear member 20A, the first gear member22A and the clutches 26, 30, 32 and brakes 34 and 36 are all coaxialwith the first axis (input shaft or member 12). The second gear member20C, the second gear member 22C and the second clutch 28 are all coaxialwith the second axis (ninth shaft or interconnecting member 68).

Referring now to FIG. 3, the operation of the embodiments of the tenspeed transmission 10 will be described. It will be appreciated that thetransmission 10 is capable of transmitting torque from the input shaftor member 12 to the output shaft or member 24 in at least ten forwardspeed or torque ratios and at least one reverse speed or torque ratio.Each forward and reverse speed or torque ratio is attained by engagementof one or more of the torque-transmitting mechanisms (i.e. first clutch26, second clutch 28, third clutch 30, fourth clutch 32, first brake 34and second brake 36), as will be explained below. FIG. 3 is a truthtable presenting the various combinations of torque-transmittingmechanisms that are activated or engaged to achieve the various gearstates. Actual numerical gear ratios of the various gear states are alsopresented although it should be appreciated that these numerical valuesare exemplary only and that they may be adjusted over significant rangesto accommodate various applications and operational criteria of thetransmission 10. An example of the gear ratios that may be obtainedusing the embodiments of the present invention are also shown in FIG. 3.Of course, other gear ratios are achievable depending on the geardiameter, gear teeth count and gear configuration selected.

To establish reverse gear, the first clutch 26, the fourth clutch 32 andthe second brake 36 are engaged or activated. The first clutch 26connects the second shaft or interconnecting member 54 with the sixthshaft or interconnecting member 62. The fourth clutch 32 connects thefifth shaft or interconnecting member 60 with the seventh shaft orinterconnecting member 64. The second brake 36 connects the fifth shaftor interconnecting member 60 to a stationary element or the transmissionhousing 50 in order to restrict member 60 from rotating relative to thetransmission housing 50. Likewise, the ten forward ratios are achievedthrough different combinations of clutch and brake engagements, as shownin FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches and the brake not specifically referenced in a givengear state are inactive or disengaged and, second of all, that duringgear shifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

The invention claimed is:
 1. A transmission comprising: an input member;an output member; a first, second and third planetary gear sets eachhaving a first, second and third member; a first and second torquetransfer assembly each having a first member and a second member; afirst interconnecting member continuously interconnecting the firstmember of the first torque transfer assembly directly to the secondmember of the first planetary gear set; a second interconnecting membercontinuously interconnecting the third member of the first planetarygear set directly to the second member of the second planetary gear set;a third interconnecting member continuously interconnecting the firstmember of the second planetary gear set directly to the first member ofthe third planetary gear set; a fourth interconnecting membercontinuously interconnecting the second member of the third planetarygear set directly to the first member of the second torque transferassembly; and six torque transmitting mechanisms each selectivelyengageable to interconnect at least one of the first members, secondmembers, third members of the first, second and third planetary gearsets, first members and second members of the first and second torquetransfer assemblies with at least one other of the first members, secondmembers, third members of the first, second and third planetary gearsets, the first members and the second members of the first and secondtorque transfer assemblies and a stationary member, and wherein the sixtorque transmitting mechanisms are each selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 2. The transmission of claim 1 wherein a first of thesix torque transmitting mechanisms is selectively engageable tointerconnect the second member of the first planetary gear set with atleast one of the first member of the second planetary gear set and firstmember of the third planetary gear set.
 3. The transmission of claim 2wherein a second of the six torque transmitting mechanisms isselectively engageable to interconnect the second member of the firsttorque transfer assembly with the second member of the second torquetransfer assembly.
 4. The transmission of claim 3 wherein a third of thesix torque transmitting mechanisms is selectively engageable tointerconnect the first member of the first planetary gear set and theinput member with at least one of the first member of the second torquetransfer assembly and the second member of the third planetary gear set.5. The transmission of claim 4 wherein a fourth of the six torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the first member of the second torque transfer assembly andthe second member of the third planetary gear set with the third memberof the second planetary gear set.
 6. The transmission of claim 5 whereina fifth of the six torque transmitting mechanisms is selectivelyengageable to interconnect the third member of the first planetary gearset and the second member of the second planetary gear set with thestationary member.
 7. The transmission of claim 6 wherein a sixth of thesix torque transmitting mechanisms is selectively engageable tointerconnect the third member of the second planetary gear set with thestationary member.
 8. The transmission of claim 1 wherein the inputmember is continuously interconnected with the first member of the firstplanetary gear set and wherein the output member is continuouslyinterconnected with the third member of the third planetary gear set. 9.The transmission of claim 1 wherein the first member of the firstplanetary gear set and the first member of the third planetary gear set,the third members of the second planetary gear sets are sun gears, thesecond members of the first, second and third planetary gear sets arecarrier members and the third members of the first and third planetarygear sets and the first member of the second planetary gear set are ringgears.
 10. The transmission of claim 1 wherein the stationary member isa transmission housing.
 11. The transmission of claim 1 wherein thefirst and the second members of the first and the second torque transferassemblies each include a first and a second sprocket.
 12. Thetransmission of claim 11 wherein the first and the second torquetransfer assemblies each further comprise a third member, wherein thethird member is a chain for coupling the first and the second sprocketto transfer torque there between.
 13. A transmission comprising: aninput member; an output member; a first, second and third planetary gearsets each having a first, second, and third member, wherein the inputmember is continuously interconnected with the first member of the firstplanetary gear set and wherein the output member is continuouslyinterconnected with the third member of the third planetary gear set; afirst and a second co-planar gear set each having a first member and asecond member; a first interconnecting member continuouslyinterconnecting the first member of the first co-planar gear set withthe second member of the first planetary gear set; a secondinterconnecting member continuously interconnecting the third member ofthe first planetary gear set with the second member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the first member of the second planetary gear set withthe first member of the third planetary gear set; a fourthinterconnecting member continuously interconnecting the second member ofthe third planetary gear set with the first member of the secondco-planar gear set; a first torque transmitting mechanism selectivelyengageable to interconnect the second member of the first planetary gearset with at least one of the first member of the second planetary gearset and first member of the third planetary gear set; a second torquetransmitting mechanism selectively engageable to interconnect the secondmember of the first co-planar gear set with the second member of thesecond co-planar gear set; a third torque transmitting mechanismselectively engageable to interconnect the first member of the firstplanetary gear set and the input member with at least one of the firstmember of the second co-planar gear set and the second member of thethird planetary gear set; a fourth torque transmitting mechanismselectively engageable to interconnect at least one of the first memberof the second co-planar gear set and the second member of the thirdplanetary gear set with the third member of the second planetary gearset; a fifth torque transmitting mechanism selectively engageable tointerconnect the third member of the first planetary gear set and thesecond member of the second planetary gear set with the stationarymember; a sixth torque transmitting mechanism selectively engageable tointerconnect the third member of the second planetary gear set with thestationary member, and wherein the torque transmitting mechanisms areeach selectively engageable in combinations of at least three toestablish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 14. Thetransmission of claim 13 wherein the first member of the first planetarygear set and the first member of the third planetary gear set, the thirdmembers of the second planetary gear sets are sun gears, the secondmembers of the first, second and third planetary gear sets are carriermembers and the third members of the first and third planetary gear setsand the first member of the second planetary gear set are ring gears.15. The transmission of claim 13 wherein the stationary member is atransmission housing.
 16. The transmission of claim 13 wherein the firstand the second members of the first and the second co-planar gear setsare a first and a second intermeshing gears.
 17. The transmission ofclaim 13 wherein the first and the second members of the first and thesecond co-planar gear sets are a first and a second sprockets.
 18. Thetransmission of claim 17 wherein the first and the second co-planar gearsets each further comprise a third member, wherein the third member is achain for coupling the first and second sprockets to transfer torquethere between.
 19. A transmission comprising: an input member; an outputmember; a first, second and third planetary gear sets each having a sungear, carrier member, and ring gear, wherein the input member iscontinuously interconnected with the sun gear of the first planetarygear set and wherein the output member is continuously interconnectedwith the ring gear of the third planetary gear set; a first and secondco-planar gear set each having a first gear and a second gear; a firstinterconnecting member continuously interconnecting the first gear ofthe first co-planar gear set with the carrier member of the firstplanetary gear set; a second interconnecting member continuouslyinterconnecting the ring gear of the first planetary gear set with thecarrier member of the second planetary gear set; a third interconnectingmember continuously interconnecting the ring gear member of the secondplanetary gear set with the sun gear of the third planetary gear set; afourth interconnecting member continuously interconnecting the carriermember of the third planetary gear set with the first gear of the secondco-planar gear set; a first torque transmitting mechanism selectivelyengageable to interconnect the carrier member of the first planetarygear set with at least one of the ring gear of the second planetary gearset and sun gear of the third planetary gear set; a second torquetransmitting mechanism selectively engageable to interconnect the secondgear of the first co-planar gear set with the second gear of the secondco-planar gear set; a third torque transmitting mechanism selectivelyengageable to interconnect the sun gear of the first planetary gear setand the input member with at least one of the first gear of the secondco-planar gear set and the second carrier of the third planetary gearset; a fourth torque transmitting mechanism selectively engageable tointerconnect at least one of the first gear of the second co-planar gearset and the carrier member of the third planetary gear set with the sungear member of the second planetary gear set; a fifth torquetransmitting mechanism selectively engageable to interconnect the ringgear of the first planetary gear set and the carrier member of thesecond planetary gear set with the stationary member; a sixth torquetransmitting mechanism selectively engageable to interconnect the sungear member of the second planetary gear set with the stationary member,and wherein the torque transmitting mechanisms are each selectivelyengageable in combinations of at least three to establish at least tenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 20. The transmission of claim 19wherein the stationary member is a transmission housing.